Hydraulic service jacks



Jan. 14, 1964 E, H, SCHUL'TZ ETAL 3,117,764

HYDRAULIC SERVICE JACKS Filed Alm-i1 e, 1961 INV EN TORS.

l: BY

EDWARD H. SCHULTZ DONALD JUDS MALZ 1- would ATTORNEYS.

United States Patent O M 3,117,764 HYDRAULIC SERJCE JACKS Edward H. Schultz and Donald Juds, Waukesha, Wis.,

assignors to Milwaukee Hydraulic Products Corporation, Milwaukee, Wis., a corporation of Wisconsin Filed Apr. 6, 1961, Ser. No. 161,093 3 Claims. (Cl. 25d-2) This invention relates to improvements in hydraulic service jacks, and more particularly to an improved jack which is faster, more convenient, and safer in operation than conventional hydraulic jacks.

It is a general object of the present invention to provide an improved hydraulic jack for use in garages, filling stations, and similar establishments, which jack is designed to raise an automobile or other vehicle principally through engagement with the bumper of said vehicle, but being constructed for engagement in other ways where required. Like the jack disclosed in my Patent No. 2,926,888, dated March 1, 1960, the present jack is provided with a pair of spaced lifting arms which are adapted to engage beneath the bumper, and which arms can be adjusted to vary the horizontal distance therebetween. With said prior jack, however, the adjustment of the lifting arms for the many various bumper designs is a relatively time-consuming task, and it is the principal object of the present invention to provide an improved construction wherein the lifting arms can be adjusted and set both faster and more easily than with the jack disclosed in said Patent No. 2,926,888 and wherein the starting height may be quickly manually varied.

A further object is to provide an improved hydraulic jack wherein the lifting arms can be manually moved upwardly into a load-engaging position, to eliminate the necessity for slowly and laboriously pumping said arms from their normal, lowered position to the point where they Contact the load, and also to permit maximum utilization of the hydraulic lifting range for raising the load.

A further object of the present invention is to provide a hydraulic service jack having a self-locking safety device adapted to eliminate the possibility of the jack being inadvertently lowered while it is supporting a vehicle or other load.

Still further objects of the present invention are to provide an improved hydraulic service jack which is relatively simple and inexpensive in construction, eilicient and reliable in operation, and otherwise well adapted for its intended purposes.

With the above and other objects in view, the invention consists of the improved hydraulic service jack, and all of its parts and combinations, as set forth in the claims, and all equivalents thereof.

ln the accompanying drawing, illustrating a complete embodiment of the preferred form of the invention, wherein the same reference numerals designate the same parts in all of the views:

FlG. 1 is a perspective View, principally in front elevation, showing the improved jack in lifting engagement with the rear bumper of an automobile;

FIG. 2 is a front elevational view of the jack; and

FIG. 3 is a fragmentary vertical sectional view of the hydraulic cylinder assemblage, showing the self-locking safety device employed in the present invention.

Referring now more particularly to the drawing, it will be seen that the improved jack comprising the present invention includes an upright outer cylinder lli'mounted in telescopic relation on an inner, fixed supporting tube li, said outer cylinder having a pair of pivoted lifting arms 13. As mentioned, said jack is generally similar in construction and operation tc the device disclosed in 3,ll7,74 Patented Jan. 14, 1954 ICC issued Patent No. 2,926,888, said lifting arms 13 being L-shaped in form to provide lower, horizontal portions i4 designed to engage beneath an automobile bumper, and said cylinder and attached lifting arms being movable vertically on the fixed inner tube ll in response to hydraulic pressure through the manipulation of a pump handle 15. The design and operation of the internal hydraulic pump members is preferably similar to that disclosed in said issued Patent No. 2,926,888, but the particular pump means employed to cause elevating extensible movement or" the outer cylinder is not critical to the present invention and has not, therefore, been described or shown in detail herein. The entire unit is mounted on a base 16 which is provided with wheels 18 to facilitate the movement of the jack from place to place.

The upper ends of the lifting arms 13 in the present invention are pivotally connected to the projecting ends of a clamping assembly i9, and as shown in FIGS. 1 and 2, said clam ing assembly normally embraces the outer cylinder itl intermediate its height. @ne of said lifting arms i3 is connected to said clamping assembly by a threaded bolt 2i) which can be turned by means of a hand wheel 2i to loosen the assembly when it is desired to relocate the clamping assembly on said upright cylinder, as will be described.

Pivotally secured to each of the lifting arms, intermediate its length, are links 22 which extend downwardly and inwardly therefrom to the lower portion of the cylinder iii, the lower ends of said links being adjustably retained in a novel bracket unit 24 which is welded or otherwise rigidly attached to the lower portion 0f said cylinder and which forms an important element of the present invention. Said bracket unit 24 includes oppositely disposed pairs of laterally extending wings which project from opposite sides of the cylinder and which are provided with elongated, generally vertically-disposed slots 25, each of said slots having a series of vertically spaced hooked portions forming notches Z6, 27, 28, and 29 (FIG. 2). The lower end of each pair of said pivoted links 22 has a horizontal pin 23 whose ends are projected into the adjacent bracket slots 25 and which is selectively insertable into one of said slot notches 26-29.

To make a quick change in the starting height of the horizontal portions 14 of the lifting arms 13, the links 22 may be manually shifted from the bracket notches in which their pins were previously set and relocated in a new set of notches. If it is desired to obtain maximum starting height, the links are positioned with the pins 23 in the uppermost notches 29, as illustrated in FIG. 1, or if less starting height is desired, said linl: pins may be positioned in one of the lower sets of notches, as shown in FIG. 2.

ln the jack disclosed in the aforementioned Patent No. 2,926,888, pivoted links similar to the links 22 of the present invention are connected to and between the lifting arms and the lower portion of the upright cylinder as in the present structure, but in said prior device ,the lower ends of said links are pivoted to the cylinlder at a fixed location. With said prior jack as well as with the present jack, in order to make a major change in the horizontal `distance between the lifting arms, the clamp assembly securing the upper ends of the lifting arms to the cylinder is loosened and said clamp assembly is slid either up or down on said outer cylinder, said clamp assembly being retightened in its new position. With the present invention, in addition, it is possible to adjust the starting'height of the lifting arms merely by manually shitting the lower ends` of the links from one set of bracket notches 2te-29 to another, as described, which operation can be done quickly and easily and which makes it un- 3 necessary to slowly pump the jack into contact with the load.

The principal advantages, therefore, which result from the novel link and bracket arrangement characterizing the present invention is that it reduces the required operation of the hydraulic pumping mechanism. Since the horizontal portions '14 of the lifting arms 13 may be raised by raising and relocating the lower ends of the links 22 as described, it is possible to manually preset said arms at a point immediately under the load and the hydraulic pumping operation need only commence from that point. Thus it is unnecessary 4to hydraulically raise the lifting7 members from their lowered position to the point where they engage the load and not only is the work of the operator minimized, but the maximum range of the hydraulic mechanism may be utilized for raising the load. Moreover, of course, the entire operation is greatly speeded by eliminating the slow pumping formerly -required in order to obtain initial engagement of the lifting arms with the object to be raised.

Referring now to FIG. 3 of the drawing, the lower portion of the telescopic outer cylinder 10 is provided with a pivotal locking pawl 3b which is designed to act as a safety catch to eliminate the possibility of the unit being inadvertently lowered while it is supporting a load, either through the accidental yturning of one of the hydraulic valves or through a malfunction of the hydraulic system. As illustrated, a spring 31 constantly urges the pawl nose portion 341 into an adjacent aperture 32 in said outer cylinder, there being a lever 33 to facilitate the withdrawal of said nose against the tension of spring 31 when desired. Formed in the upper portion of the fixed supporting member 11 is a series of vertically-spaced apertures 34 in circumferential alignment with said outer cylinder aperture 32. The upper edge of the pawl nose 30 is obliquely angled so that said pawl will slip by the holes 34 `during upward travel of the outer cylinder 10. The lower pawl edge is perpendicular to the surface of the cylinder so that when said cylinder and attached lifting arms 13 are in a raised position the pawl may either engage and remain within an aperture 34 in the inner supporting member, or will soon engage within one of such apertures if the cylinder 10 should start to slip downwardlly, and will thus prevent the load from being inadvertently lowered. To release the locking pawl when it is desired to lower the load, the pawl nose may be withdrawn from said registering apertures through manipulation of the lever 33, the jack lbeing lowered in the conventional manner.

From the foregoing detailed description it will be seen that the present invention provides a hydraulic jack which is an improvement on the jack disclosed in my issued Patent No. 2,926,888, dated March 1, 1960 ln the use of the present jack, the lifting arms may be quickly and easily preset as desired, merely by manually adjusting the position of the links 22 within the bracket 24. Thus the use of said bracket and link mechanism minimizes the work of the operator and increases the speed of the operation, as described. Moreover, when the present jack is in an extended condition the locking pawl 30 functions either to securely maintain the load in a raised position, or as a safety catch to eliminate the possibility of accident or injury, or for both purposes.

It is to be understood, of course, that various changes or modifications inthe structure herein described and illustrated will undoubtedly occur Vto persons skilled in the art, and all of such changes or :modifications are contemplated as may come within the scope of the following claims.

What -we claim is:

1. In a hydraulic service jack of the type having a base, having an lupright supporting member mounted on said base, having an elongated lifting member extensibly mounted on said upright supporting member, having means for causing elevating extensible movement of said lifting member, having a pair of normally depending lifting arms pivotally connected at their upper ends to said lifting member and having lower end load-engaging portions, and having a link pivotally connected to each lifting arm intermediate its length, the improvement comprising: cooperating means on the lower ends of said links and on the lower portion of said extensible lifting member for effecting a force-transmitting engagement Ibetween said lower ends of the lin-ks and said lifting member, said means on the lower end of the lifting member including vertically-spaced connected notches, and said means on each link including a pin engageable in one of said notches to preset the starting height of said loadengaging portions of the lifting arms.

2. In a hydraulic service jack of the type having a base, having an upright supporting member mounted on said base, having an elongated lifting member extensibly mounted on said upright supporting member, having means for causing elevating extensible movement of said lifting member, and having a pair of normally depending lifting arms pivotally connected at their upper ends to said lifting member and having lower end load-engaging portions, the improvement comprising: brackets projecting laterally from opposite sides of the lower portion of said lifting member below said lifting arm connection, each of said brackets beinU provided with a generally vertically disposed slot, each slot including a vertical series of outwardly and upwardly inclined hook-shaped sections with stem and `upper hook portions, the latter being hooked inwardly to connect with a stem portion thereabove, a link pivotally connected at its upper end to each lifting arm and projecting downwardly and inwardly to the adjacent bracket, and a transverse pin on the lower end of each link for movement in the slot of the adjacent bracket, the extremity of each of said hook portions forming a notch to effect a force-transmitting engagement with said pin and link, and each pin being movable in its slot from one notch to another to preset the starting height of the load-engaging portions of said lifting arms.

3. In a hydraulic service jack of the type having a base, having an upright supporting member mounted on said base, having an elongated lifting member extensibly mounted on said upright supporting member, having means for causing elevating extensible movement of said :lifting member, having a pair of normally depending lifting arms pivotally connected at their upper ends to said lifting member and having lower end load-engaging portions, and having a link pivotally connected to each lifting arm intermediate its length, the improvement comprising: cooperating means on the lower end of each link member and on the lower portion of said extensible lifting member and comprising vertically spaced apertures on one of said members and a pin on the other member engageable with a selected aperture for effecting a force transmitting engagement between the lower end of each link and said lifting member at a selected one of several vertically spaced locations to preset the starting height of said load engaging portions of the lifting arms.

References Cited in the le of this patent UNITED STATES PATENTS 667,992 Patzold Feb. 12, 1901 2,368,192 v Bishop et al Jan. 30, 1945 2,469,670 Thompson May 10, 1949 2,549,996 Walsh Apr. 24, 1951 2,664,073 Pine Dec. 29, 1953 2,805,839 Branick Sept. 10, 1957 2,806,686 Miller Sept.Y 17, 1957 2,895,712 tovern et al. July 21, 1959 2,909,358 Southerwick Oct. 20, 1959 2,926,888 Schultz Mar. 1, 1960 2,947,513 Nolden et al Aug. 2, 1960 2,973,184 Trautman etal Feb. 28, 1961 3,058,602 Kilman Oct. 16, 1962 

1. IN A HYDRAULIC SERVICE JACK OF THE TYPE HAVING A BASE, HAVING AN UPRIGHT SUPPORTING MEMBER MOUNTED ON SAID BASE, HAVING AN ELONGATED LIFTING MEMBER EXTENSIBLY MOUNTED ON SAID UPRIGHT SUPPORTING MEMBER, HAVING MEANS FOR CAUSING ELEVATING EXTENSIBLE MOVEMENT OF SAID LIFTING MEMBER, HAVING A PAIR OF NORMALLY DEPENDING LIFTING ARMS PIVOTALLY CONNECTED AT THEIR UPPER ENDS TO SAID LIFTING MEMBER AND HAVING LOWER END LOAD-ENGAGING PORTIONS, AND HAVING A LINK PIVOTALLY CONNECTED TO EACH LIFTING ARM INTERMEDIATE ITS LENGTH, THE IMPROVEMENT COMPRISING: COOPERATING MEANS ON THE LOWER ENDS OF SAID LINKS AND ON THE LOWER PORTION OF SAID EXTENSIBLE LIFTING 